Cooling apparatus

ABSTRACT

A cooling apparatus for an electronic or computing device includes a base for thermal coupling to a surface of the electronic or computing device and a cover spaced from the base. A nozzle plate is disposed between the base and the cover to partially define an inlet volume and an outlet volume. Cooling fluid enters the inlet volume and passes through the nozzle plate to the outlet volume and out of the apparatus. The nozzle plate includes a plurality of flow paths through which the cooling fluid passes from the inlet volume to the outlet volume. The flow paths cause the fluid to exit the nozzle plate as transversely expanding fluid jets.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation application which claims priority to commonlyassigned, co-pending U.S. patent application Ser. No. 17/023,028, filedSep. 16, 2020. Application Ser. No. 17/023,028 is fully incorporatedherein by reference.

TECHNICAL FIELD

This patent disclosure relates generally to cooling apparatuses and,more particularly, to fluid-based cooling systems for use withmechanical, electrical, and/or electromechanical systems.

BACKGROUND

Advances in semiconductors and related fields have resulted in smallerelectronic and computing devices having increased power and performance.One result of tasking integrated circuits, servers, processors, and thelike, with higher functionality is increased heat generation. However,this increased heat, often coupled with a decreased device size, canresult in destructively high heat densities in some devices. Failure toreduce or remove this heat can result in device underperformance and/orpremature device failure.

Many conventional cooling methods have been used to reduce heat inelectronic and computing devices. For instance, heat sinks have beenused in some instances to draw heat away from the heat-generatingcomponents. Conventional heat sinks may include thermally conductivematerials in proximity of the heat generating components that dissipateheat through an exposed surface. In some instances, air can be passedover the exposed surface of the heat sink to aid in heat dissipation.More recently, pumped liquid cooling systems have been introduced thatprovide improved thermal performance. In these systems, a liquid coolantis passed through an enclosed volume attached to the heat generatingcomponent or component to be cooled. A heat sink may be included in thevolume and often includes a plurality of channels that increase thesurface area of the heat sink. Advances in these liquid cooling systemshave generally focused on further increasing the surface area of theheat sink, e.g., by reducing fin thickness and/or increasing findensity, and/or on generating two-phase fluid, e.g., by atomizing theliquid through increased pressure or other measures. However, fins havea finite thinness, and systems that space fins too closely have failedwhen particulates and/or other debris carried by the cooling liquid gettrapped between the fins. Moreover, attempts to atomize cooling fluidhave proven difficult and expensive. Accordingly, there is the need inthe art for improved cooling apparatuses that effectively remove heatfrom electronic and computing devices.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view of a cooling apparatus inaccordance with aspects of this disclosure.

FIG. 2 is a perspective view of the cooling apparatus of FIG. 1assembled and in a configuration in which a cover is rotated 90-degreesrelative to the view of FIG. 1 , in accordance with aspects of thisdisclosure.

FIGS. 3A, 3B, and 3C are, respectively, a top plan view, a bottom planview, and a cross-sectional view along the line 3C-3C in FIG. 3A of anozzle plate for use in a cooling apparatus, in accordance with aspectsof this disclosure.

FIGS. 4A, 4B, and 4C are, respectively, a bottom plan view, a firstcross-sectional view along the line 4B-4B in FIG. 4A, and a secondcross-sectional view along the line 4C-4C in FIG. 4A of a cover for usein a cooling apparatus, in accordance with aspects of this disclosure.

FIGS. 5A and 5B are, respectively, cross-sectional views along thesection lines 5A-5A and 5B-5B in FIG. 2 , in accordance with aspects ofthis disclosure.

FIGS. 6A-6C are example nozzle plates for use in a cooling apparatus andhaving differing inlet profiles, in accordance with aspects of thisdisclosure.

FIGS. 7A and 7B are example nozzle plates for use in a cooling apparatusand having differing inlet profiles, in accordance with aspects of thisdisclosure.

FIGS. 8A and 8B are cross-sectional views of example nozzle plates foruse in a cooling apparatus and illustrating varied channel profiles, inaccordance with aspects of this disclosure.

DETAILED DESCRIPTION

This disclosure generally relates to cooling apparatuses, and, moreparticularly, to cooling apparatuses configured for securement tocomputing and/or electronic components to remove heat from thosedevices. In embodiments described herein, the cooling apparatuses may beconfigured for securement to a server component, a processor, a chip, anintegrated circuit, and/or one or more related components. However, thisdisclosure is not limited to use with computing components, and insteadmay be used with many types of components and/or assemblies that benefitfrom improved heat dissipation, as described herein. Wherever possible,the same reference numbers will be used through the drawings to refer tothe same features.

FIG. 1 is an exploded perspective view of a cooling apparatus 100according to aspects of this disclosure. The cooling apparatus 100includes a base 102, a frame 104 configured for securement to the base102, a nozzle plate 106 supported by the frame 104, and a cover 108 thatcooperatively engages, and is securable to, the frame 104. The base 102,the frame 104, the nozzle plate 106, and the cover 108 will be describedbriefly in connection with FIG. 1 and detailed further throughout thisspecification.

The base 102 is generally configured for securement on, or proximate to,a surface to be cooled. As illustrated, the base 102 has a generallyplanar bottom surface 110 (obscured in FIG. 1 ) and a generally planartop surface 112. The top surface 112 may be spaced from the bottomsurface 110 by a thickness of the base 102. In some examples, thethickness of the base is substantially uniform, e.g., such that the topsurface 112 is substantially parallel to the bottom surface 110. As alsoillustrated in FIG. 1 , the base 102 includes a plurality of fins 114extending from the top surface 112, e.g., in a direction away from thebottom surface 110. The fins 114 comprise a plurality of elongate,parallel protrusions extending in the x-dimension of FIG. 1 and raisinga height above the top surface 112 in the z-dimension of FIG. 1 .

In examples, the base 102 may be made of a material having a highthermal conductivity. For example, the base 102 may be fabricated ofcopper or aluminum. In operation, the base 102 may be secured to asurface of a device to be cooled using the cooling apparatus 100.Without limitation, the bottom surface 110 of the base 102 may besecured to contact a surface of an electronic and/or computing device.In some examples, the fins 114 may be formed by conventional machiningtechniques, such as milling, skiving, or the like. Although FIG. 1illustrates twenty substantially identical, equally spaced fins 114,this is for example only. In other examples, the fins 114 may bedifferently sized (e.g., taller, wider), differently shaped (e.g.,contoured, stepped), differently oriented (e.g., angled other thanshown), differently spaced (e.g., more or less densely arranged), and/orotherwise differently configured. Moreover, more or fewer fins may beused. Moreover, although the fins 114 are illustrated in FIG. 1 , inother aspects of this disclosure, the fins 114 may be embodied as othertypes of surface features, such as pins, columns, dimples, indents, orthe like. In examples, the base 102 may include any configuration and/orfeatures that increase surface area or increase heat dissipation. Inother examples, the base 102 may not include such features. For example,instead of the fins 114, the base 102 may include a substantiallyplanar, continuous surface, e.g., the top surface 112. In still furtherexamples, the base 102 may include a single, continuous surface spacedfrom the top surface 112. Such a surface may be provided by a protrusionhaving a length corresponding to the length (in the x-dimension) of theillustrated fins 114, a width corresponding to the collective width ofall of the fins 114 (including the channels formed therebetween—in they-dimension), and/or a height corresponding to a height (in thez-dimension) of the fins 114, although other shapes, sizes, and/or thelike may alternatively be used.

As noted above, the frame 104 is configured to be secured to the base102. FIG. 1 shows that the frame 104 generally includes a continuousside wall 116 defining a perimeter. In this example, the sidewall 116 isgenerally square, having four equal sides. The sidewall 116 isconfigured such that when the frame 104 secured to the base 102, abottom surface 118 (obscured in FIG. 1 ) of the frame 104 contacts (oris otherwise sealed relative to) the top surface 112 of the base 102,and the sidewall 116 is disposed around the fins 114.

The frame 104 also includes a first notch 122 a, a second notch 122 b, athird notch 122 c, and a fourth notch 122 d (collectively referred toherein as the notches 122). The notches 122 are substantially identical,with one being provided on each segment of the sidewall 116. In moredetail, each of the notches 122 is a cutout comprising a break in thesidewall 116 and having a predetermined width. That is, the notches aresubstantially identical. Moreover, the notches 122 are arranged atpredetermined positions, e.g., at equal distances from an adjacentsidewall. As will be described in more detail herein, the notches 122act as alignment members that promote selective alignment of the cover108 relative to the frame 104.

The frame 104 also includes a first shelf or ledge 124 a and a secondshelf or ledge 124 b on an inner periphery of the sidewall 116. Thefirst ledge 124 a provides a surface that supports the nozzle plate 106,e.g., by contacting an outer periphery of a bottom surface 130 (obscuredin FIG. 1 ) of the nozzle plate 106. The second ledge 124 b provides asurface that supports the cover 108. In the illustrated example, aninner surface of the sidewall 116 has a stepped profile, such that alower segment 126 of the sidewall 116 extends further, e.g., toward acenter of an area defined by the sidewall 116, than an upper segment 128of the sidewall 116. This stepped profile provides the first ledge 124 aand the second ledge 124 b at the inner periphery of the sidewall.However, in the illustrated example, the lower segment 126 and the uppersegment 128 are continuous on an outer surface of the sidewall 116,although such may not be required. As also illustrated in FIG. 1 , thenotches 122 extend (in the z-dimension of FIG. 1 ) from the top surface120 of the sidewall 116 to the second ledge 124 b. However, the notches122 can be shallower or deeper than is illustrated.

The frame 104 also includes an outlet port 132 extending from thesidewall 116. The outlet port 132 defines an opening 134 to a passagewaythat extends through the sidewall 116 and opens to the volume defined bythe sidewall 116. As detailed further herein, fluid that contacts thefins 114 of the base 102 leaves the cooling apparatus 100 via the outletport 132. The outlet port 132 is configured as a nozzle in the exampleof FIG. 1 , although the outlet port 132 may take other forms in otherembodiments. For example, and without limitation, the outlet port 132may include a push-to-connect fitting, a compression fitting, a flarefitting, or other fitting. In examples, the outlet port is configured tosecure a conduit, e.g., a hose, tubing, or the like, to the frame 104.More specifically, fluid exiting the cooling apparatus 100 via theoutlet port 132 is carried away, e.g., to a pump, heat exchanger, orother component, via the conduit attached to the outlet port 132.

The nozzle plate 106 is generally configured to control the flow offluid, e.g., single-phase fluid, for contact with the fins 114 of thebase 102. The nozzle plate 106 is a generally planar member having asubstantially constant thickness between a top surface 136 and thebottom surface 130. The nozzle plate 106 has a plurality of flow paths138 formed therein. In more detail, the flow paths 138 extend throughthe nozzle plate 106 from an inlet opening in the top surface 136 to anoutlet opening in the bottom surface 130. As detailed further herein,the flow paths 138 are configured such that fluid entering the flowpaths 138, e.g., from above the top surface 136 of the nozzle plate 106,leaves the flow paths 138, e.g., from the bottom surface 130 of thenozzle plate 106, as laterally-expanding, single phase fluid jets.Specifically, the laterally-expanding fluid jets impinge on the base102, e.g., the fins 114 of the base 102, and then exit the coolingapparatus 100 via the outlet port 132, as discussed above.

The nozzle plate 106 can include an array of flow paths 138. In theexample of FIG. 1 , the flow paths are arranged in a plurality of rowsspaced in the x-dimension and generally extending in the y-dimension ofFIG. 1 . Also in the illustrated example, flow paths in one row areoffset, e.g., in the x-dimension, relative to flow paths in an adjacentrow or adjacent rows. By staggering the flow paths 138 in this manner,impingement of cooling fluid on the fins 114 of the base 102 may beincreased. However, the illustrated arrangement is for example only andother configurations will be appreciated. For instance, the flow pathsmay be aligned in both the x- and y-dimensions. Also, more or fewer flowpaths may be provided. The nozzle plate 106 is described in more detailbelow, e.g., in connection with FIGS. 3A-3C, and modifications to thenozzle plate are illustrated in FIGS. 6A-6C, 7A, 7B, 8A, and 8B,described further below.

The cover 108 is generally configured for placement over the nozzleplate 106 and in cooperation with the frame 104. Although obscured inFIG. 1 , an underside of the cover 108, e.g., facing the top surface 136of the nozzle plate 106, includes a cavity (shown and described in moredetail in connection with FIGS. 4A-4C) such that when the cover 108 isplaced on the nozzle plate 106, an outer periphery of the underside ofthe cover 108 rests on the second ledge 124 b and may partially contactan outer periphery of the top surface 136 of the nozzle plate 106. Asalso illustrated, the cover 108 is defined on lateral edges by segmentsof a sidewall 140. The sidewall 140 is shaped and sized to be receivedwithin an opening defined by the sidewall 116 of the frame 104. Thecover 108 also includes a first tab 142 a, a second tab 142 b, a thirdtab 142 c, and a fourth tab 142 d (collectively, the tabs 142) extendinglaterally from the sidewall 140. The tabs 142 are sized and positionedto be received in the notches 122. That is, the tabs 142 are alignmentfeatures that cooperate with the notches 122 to position the cover 108relative to the frame 104.

The cover 108 also includes an inlet port 144 extending from the secondtab 142 b. The inlet port 144 defines an opening (not visible in FIG. 1) that extends through the second tab 142 b and the sidewall 140 andopens to the volume defined by the cavity in the underside of the cover108 (shown in detail in FIGS. 4A and 4B, discussed below). As detailedfurther herein, fluid enters the cooling apparatus 100 via the inletport 144. The inlet port 144 is configured as a nozzle or nipple in theexample of FIG. 1 , although the inlet port 144 may take other forms inother embodiments. For example, and without limitation, the inlet port144 may include a push-to-connect fitting, a compression fitting, aflare fitting, or other fitting. In examples, the inlet port 144 isconfigured to secure a conduit, e.g., a hose, tubing, or the like, tothe cover 108. In some examples, fluid entering the cooling apparatus100 via the inlet port 144 may be a cooled fluid supplied by a pump orother fluid source via the conduit secured to the inlet port 144.

The tabs 142 and the notches 122 are configured to provide selectiveorientation of the inlet port 144 relative to the outlet port 132. Forinstance, in the example shown, the inlet port 144 is rotated 90-degreesrelative to the outlet port 132. However, in other configurations, theinlet port is otherwise arranged. For instance, if the cover 108 isturned 90-degrees clockwise relative to the illustrated arrangement, thesecond tab 142 b would be arranged to be received in the third notch 122c, the third tab 142 c would be arranged to be received in the fourthnotch 122 d, and so forth. In this configuration, the inlet port 144 andthe outlet port 132 would be substantially parallel. Thus, the coolingapparatus 100 may be configured in four different orientations, e.g., byrotating the cover 108 in 90-degree increments. For example, differentconfigurations may provide greater flexibility in installation andconnection of the cooling apparatus to conduits or the like. In theillustrated example, four configurations are provided by the generallysquare shape of the frame 104 (e.g., the sidewall 116) and the cover 108(e.g., the sidewall 140). Other shapes may provide more or fewerconfigurations. For instance, if the frame 104 and the cover 108 aresubstantially rectangular, only two orientations may be possible.However, additional-sided polygons can provide additional orientations.For instances, if the frame 104 and the cover 108 are embodied ashexagons, notches like the notches 122 can be formed in each of the sixsides of the frame and tabs like the tabs 142 can be formed on each ofsix sides, which could allow for six configurations. Moreover, acircular shape may provide for additional configurations, e.g.,numbering as many as the notches and tabs formed on the cooperatingcircular frame 104 and the circular cover 108. This disclosure is alsonot limited to the notches 122 and the tabs 142 as alignment features.In the case of a circular shape for the frame 104 and the cover 108, thecover 108 may rotate freely relative to the circular frame 104 and otherfastening techniques may be implemented to secure the cover 108 to theframe 104. Without limitation, mechanical fasteners, latches,compression features, snap features, or the like may be used to securethe cover 108 to the frame 104.

Although the cooling apparatus 100 is illustrated as the fourcomponents, e.g., the base 102, the frame 104, the nozzle plate 106, andthe cover 108, some additional components are omitted for clarity. Forinstance, gaskets, seals, and/or the like may be situated betweenadjacent components to prevent fluid leaking from volumes defined by thecomponents, as described further herein. Moreover, fasteners are notillustrated. In at least some examples, and without limitation, theframe 104 may be secured to the base 102 using conventional fasteners,e.g., bolts or screws, that pass through mounting holes (not shown)extending from a top surface 120 of the frame 104, through the sidewall116, and through the bottom surface 118 into threaded holes (not shown)in the base 102. This is for example only; other fastening arrangementsare contemplated. In at least one other configuration, threadedfasteners may be passed through the base 102 and received in threadedopening in the frame 104 or the cover 108. Moreover, and although notillustrated in FIG. 1 , a gasket may be provided between the top surface112 of the base 102 and the bottom surface 118 of the frame 104 to sealthe surfaces. A channel or other feature may be formed in one or both ofthe base 102 and the frame 104 to retain the gasket. Gaskets may be usedsimilarly between abutting surfaces when a seal is desired. Also inalternative examples, the four illustrated components may be embodied asmore or fewer components. For example, certain of the components, likethe base 102 and/or the frame 104 may be fabricated as two or morecomponents. Similarly, in some examples two or more of the frame 104,the nozzle plate 106, and/or the cover 108 may be formed as a unitarypiece. Without limitation, the frame 104 and the cover 108 may be formedas a unitary piece that receives the nozzle plate and attaches to thebase 102, for instance. This example may not provide for selectiveconfiguration of the inlet port 144 and/or the outlet port 132, as justdescribed.

FIG. 2 illustrates the cooling apparatus 100 in an assembled state. Asillustrated, the cooling apparatus 100 is a compact, low-profile system.In the assembled state, the frame 104 is coupled to the base 102 and thecover 108 is coupled to the frame 104. The nozzle plate 106 is disposedbetween the cover 108 and the frame 104 and is not visible in FIG. 2 .When assembled, the tabs 142 are received in the notches 122 in anorientation rotated relative to the configuration shown in FIG. 1 . Morespecifically, the cover 108 is rotated clockwise 90-degrees relative tothe orientation shown in FIG. 1 . Accordingly, the inlet 144 and theoutlet 132 are adjacent each other and generally parallel, as opposed tothe normal relationship shown in FIG. 1 . In some examples, the base 102may be formed of a high thermal-conductivity material, such as copper oraluminum. The frame 104, the cooling plate 106, and/or the cover 108 maybe formed of a different material, such as a polymer, a metal, or othermaterial. Although not illustrated, mounting holes may be formed throughthe base 102 to facilitate mounting of the assembled cooling apparatus100 to a heat-generating component. Additional aspects of the coolingapparatus 100 will now be described in more detail.

FIGS. 3A-3C show the nozzle plate 106 in more detail. More specifically,FIG. 3A is a top view of the nozzle plate, showing the top surface 136of the nozzle plate 106, FIG. 3B is a bottom view, showing the bottomsurface 130 of the nozzle plate 106, and FIG. 3C is a cross-sectionalview taken along section line 3C-3C in FIG. 3A. As generally describedabove in connection with FIG. 1 , the nozzle plate 106 includes a numberof flow paths (the flow paths 138) formed through the nozzle plate 106and through which fluid can pass through the nozzle pate 106. Fluidintroduced at the top surface 136 of the nozzle plate 106 passes throughthe flow paths and exits proximate the bottom surface 130 of the nozzleplate 106. FIG. 3A shows an array of inlets 302 at the top surface 136.A magnified portion 304 of FIG. 3A shows one of the inlets 302 in moredetail. As illustrated, the inlet 302 is generally triangular having ahypotenuse extending generally laterally, e.g., in the y-dimension, andlegs extending at 45-degree angles to form an apex spaced from thehypotenuse in the x-dimension. In this arrangement, a length of thehypotenuse is a lateral width of the inlet, and a distance between thehypotenuse and the apex is a thickness of the inlet, t_(i).

FIG. 3B shows an array of outlets 306 formed in the bottom surface 130of the nozzle plate 106. As will be appreciated, each of the outlets 306is associated with one of the inlets 302. Specifically, each of theinlets 302 is connected to one of the outlets 306 via a channel, asdescribed further herein. As best shown in the magnified portion 308 ofFIG. 3B, each of the outlets 306 is generally trapezoidal in shapehaving a first, longer leg 310, a second, shorter leg 312 and oppositeside edges 314. In this example, the first leg 310 is spaced from thesecond leg 312, e.g., in the x-dimension, by an outlet thickness, to. Awidth of the outlet, w_(o), e.g., measured in the y-dimension, is thelength of the first leg 310. In this example, the side edges 214 areangled relative to the first leg 310 and the second leg 312 by about45-degrees, although other angles may be used.

As will be appreciated from FIG. 3A and FIG. 3B, the inlet width, w_(i),is significantly smaller than the outlet width, w_(o). Also in theillustrated example, the inlet thickness, is smaller than the outletthickness, t₀, although, as detailed further herein, such may not berequired. In aspects of this disclosure, an area of one of the inlets302, e.g., a two-dimensional area measured in the plane of the topsurface 136, is smaller than an area of one of the outlets 306, e.g., atwo-dimensional area of the outlet 306 measured in the plane of thebottom surface 130 of the nozzle plate 106. Accordingly, fluidintroduced at the inlet 302 expands as it travels through the nozzleplate 106 and exits via the outlets 306. In particular, the fluidexpands to create transversely expanding single phase fluid jetsproximate the outlets 306, as described further herein. Although theexample of FIGS. 3A and 3B show expansion from the inlet 302 to theoutlet 306 in the y-direction, e.g., laterally, other implementationsmay provide for transverse expansion in any other direction. Withoutlimitation, the outlet thickness, t_(o), may be larger than the inletthickness, whereas the inlet width, w_(i), and the outlet width w_(o),may be substantially the same. In other examples, the expansion mayoccur in both the thickness and width and/or in other directions.

FIG. 3C is a cross-section of the nozzle plate 106 taken along sectionline 3C-3C in FIG. 3A and shows a channel 316 extending between one ofthe inlets 302 and one of the outlets 306. Channels similar to or thesame as the channel 316 may be provided to connect other of the inlets302 with other of the outlets 306. More specifically, and as shown bestin a magnified portion 318, the channel 316 extends from one of theinlets 302 to one of the outlets 306 through a thickness of the nozzleplate, t_(p). In this example, the channel 316 is angled relative toboth the top surface 136 and the bottom surface 130 of the nozzle plate106. In the illustrated cross-section, the channel 316 is at a channelangle θ relative to the bottom surface 130 (and the top surface 136). Inthe illustrated example, the angle θ is approximately 45-degrees,although the channel angle θ may be varied. As will be appreciated,varying the channel angle θ will alter an angle at which fluid exitingthe outlet 306 will impinge the base 102, as described further herein.As also illustrated in the magnified portion 318, the channel 316 has athickness, t_(n). The thickness is substantially uniform from a positionproximate the inlet 302 to the outlet 306. According to thisconfiguration, once fluid enters the channel 316 via the inlet 302,fluid will laterally disperse, e.g., in a direction normal to theviewing plane of FIG. 3C, because the channel expands laterally, e.g.,in the y-dimension.

As illustrated further in FIG. 3C, the channel 316 does not extendentirely through the top surface 136. Instead, an undercut 318 isprovided proximate the top surface 136, resulting in the inlet 302having a smaller opening in the x-dimension than the outlet 306. In theillustrated embodiment, the undercut 318 extends at approximate90-degrees relative to the axial direction of the channel 316, e.g.,normal to the channel angle θ. The undercut 318, along with the inlet302 creates a nozzle proximate the inlet 302. As illustrated in FIG. 3C,the undercut 318 extends a depth, e.g., a nozzle depth, d_(n), in thez-dimension. In some examples, geometries of the inlet 302, the channel316, and/or the undercut 318 may alter flow properties of the fluidpassing through the nozzle plate 106, e.g., without changing a phase ofthe fluid. Without limitation, the inlet 302, the channel 316, and/orthe undercut 318 may cause fluid, such as water, passing through theinlet 302 to disperse transversely outwardly. These transverselyexpanding jets may further expand, as constrained by the channel 316, tothe outlet 306. Thus, in some examples, a nozzle-type structureproximate the inlet 302 causes an initial transversely expandingdispersion of fluid, and the shape of the channel 316, e.g., having atransversely expanding shape, may promote further, constraineddispersion of the fluid.

The geometry illustrated in FIG. 3C, e.g., with the undercut 318, mayresult from manufacture of the nozzle plate 106. In some examples, thenozzle plate 106 may be formed using conventional additive orsubtractive machining techniques. In an additive process, such asinjection or other molding, the flow paths 138 may be formed by moldingaround an array of plates provided in the mold. For instance, squareplates having a thickness corresponding to the nozzle thickness, tn, maybe angled at an angle corresponding to the channel angle θ, such that acorner of each of the square plates is highest, e.g., in the z-dimensionof FIG. 3C. Molding around the plates such that a bottom surface of thesquare plates at the highest corner is covered in mold material willresult in the undercut 318. Such a technique will also result in thetriangular-shaped inlet 302 and the trapezoidal-shaped outlet. In asubtractive machining technique, a cutting tool may be plunged orotherwise inserted into the nozzle plate 106 along the channel angle θ,to form the channel 316, including the undercut 318.

As described above, the undercut 318 may function with the inlet 302 andthe channel 316 to cause fluid entering the inlet 302 to createtransversely-expanding single phase fluid jets. In examples, thegeometries of the inlet 302, the outlet 304, the channel 316, and/or theundercut 318 may be altered to create different transversely expandingjets. For instance, the rate at which the channel 316 in one or both ofthe width and height dimensions may alter the jet exiting the outlet304. Similarly, varying the angle of the undercut 318 and/or the channel316 can cause different behavior at the inlet. In the illustratedexample the undercut 318 and the channel 316 result in sharp edges atthe periphery of the inlet 302, e.g., rapidly increasing in diameter atdepths from the top surface 136 of the nozzle plate 106. In someexamples, varying the thickness of the nozzle plate, t_(p), and/or thedepth of the undercut, e.g., d_(n), may vary the flow passing throughthe inlet. For instance, and without limitation, the depth of theundercut 318 may be smaller than a diameter of the inlet 302. Fornon-circular inlets, e.g., the triangular inlet 302, the hydraulicdiameter of the inlet may be greater than the depth, d_(n). In otherexamples, the diameter, e.g., hydraulic diameter, may be the same as, orlarger than, the depth, d_(n).

The arrangement of FIGS. 3A, 3B, and 3C, provides for an examplearrangement in which water jets emanating from the outlets 306 include atransverse velocity component, e.g., angled relative to an axialdirection of the flow, such as in the y-dimension of FIG. 3A and/orangled relative to the channel angle θ in the x-z plane. In theillustrated example of FIGS. 3A-3C, the shape of the inlet 302 and theoutlet 306 in FIG. 3A will result in transversely expanding jets thatare generally fan-shaped, e.g., expanding in the y-dimension, but havinga generally constant thickness, e.g., corresponding to the nozzlethickness, t_(n). As detailed above, in the illustrated example, theundercut 318, together with inlet 302 and the channel 316, may act as athin orifice or nozzle, causing fluid entering the inlet 302 totransversely expand as it enters the channel 316. This transverseexpansion results in a single-phase jet, e.g., as opposed to an atomizedspray. Accordingly, aspects of this disclosure have a lower pressuredrop than two-phase (e.g., liquid to gas) designs, but providetransverse expansion for greater surface area coverage, as describedherein. Moreover, because the channels 316 transversely expand, e.g., inthe y-dimension of FIGS. 3A-3C, the jets further expand as they pass toand through the outlet 304. In addition, because the channels 316 aregenerally aligned at 45-degrees relative to the bottom surface 130 ofthe nozzle plate 106, the transversely expanding jets will exit theoutlets 306 generally at a 45-degree angle. The transversely expandingjets are shown in more detail in FIGS. 5A and 5B, detailed below.

The shapes, widths, thicknesses, and angles illustrated in FIGS. 3A, 3B,and 3C are for example, and modifications to one or more of theseparameters may result in different outcomes, e.g., different shapes,sizes, impingement angles, or the like. In one example, the platethickness, t_(p), may be up to about 2.5 mm and the outlet width w_(o),may also be up to about 2.5 mm. The inlet width, or a hydraulic diameterof the inlet, may be less than about 0.5 mm and the channel angle, asnoted above, may be about 45-degrees. In other examples, however, theplate thickness, t_(p), and the outlet width w_(o), may vary from about0.1 mm to about 10 mm, the inlet width, or hydraulic diameter, may be onthe order of from about 1 μm to about 1 mm, and the channel angle mayvary from about 10-degrees to 90-degrees.

FIGS. 4A-4C show the cover 108 in more detail. More specifically, FIG.4A is a bottom view of the cover 108, FIG. 4B is a cross-sectional viewalong section line 4B-4B in FIG. 4A, and FIG. 4C is a cross-sectionalview along section line 4C-4C in FIG. 4A. These figures will bediscussed in turn.

As shown in FIG. 4A, the cavity 108 defines a cavity 402 generallycircumscribed by the sidewall 140 and extending from a bottom surface404 of the cavity 402 to an upper cavity surface 406. The tabs 142 alsoare illustrated, as is the inlet port 144. The inlet port 144 defines aportion of a passageway 408 that also passes through the associated oneof the tabs 142 and into the cavity 402. A flow diverter 410 optionallyis formed on the upper cavity surface 406, generally as a protrusionextending from the upper cavity surface 406 into the cavity 402. Theflow diverter 410 is an elongate feature, having a ridge 412 or apexgenerally aligned with the passageway 408 and having opposite, inclinedsides 414 extending from the ridge 412 to the upper cavity surface 406.A leading edge 416 of the flow diverter, e.g., proximate the passageway408 may also be inclined from a termination of the ridge 412 to theupper cavity surface 406. The leading edge 416 is illustrated as beinggenerally arcuate, although other shapes, e.g., angled, straight, or thelike, may alternatively be used.

FIG. 4B shows additional features of the cover 108. More specifically,FIG. 4B is a cross-sectional view that bisects the flow diverter 410,e.g., along the ridge 412. As shown in FIG. B, the passageway 406extends axially from a first opening 418 of the inlet port 144 to asecond opening 420 at the cavity 402. As shown, the leading edge 416 isangled relative to the bottom surface 404 of the cover 108. In thisexample, the ridge 412 is substantially parallel to the bottom surface404, although such is not required.

FIG. 4C shows still further features of the cover 108. Morespecifically, FIG. 4C is a cross-sectional view parallel to thecross-sectional view of FIG. 4B, but laterally away from the flowdiverter 108. FIG. 4C shows the upper cavity surface 406 in more detail.In some examples of this disclosure, the upper cavity surface 406 may beangled relative to the bottom surface 404, such that the cavity 402 doesnot have a uniform depth. In this example, a distance between the uppercavity surface 406 and the bottom surface 404 is larger proximate thenozzle and smaller farther from the nozzle. In some examples, thedistance from the upper cavity surface 406 may vary from about 0.1 mm orsmaller to about 1.0 mm or larger. As also shown in FIG. 4C, because theupper cavity surface 406 is not parallel to the bottom surface 404, thesides 414 vary in length, e.g., from the ridge 412 to the upper cavitysurface 406.

In operation, the inner cavity 402 defines a portion of an inlet volume,e.g., for receiving cooling fluid that passes through the nozzle plate.Features of the cover 108 also aid in dispersion of the fluid in thecavity 402. For instance, the flow diverter 408 functions to laterally(relative to the axial direction of the passageway 408) divert coolingfluid that enters the cavity 402. More specifically, and as illustratedby the arrows in FIG. 4A, fluid that enters the inlet port 144 generallypasses axially through the passageway 408 and enters the cavity 402 at asingle orifice. The flow diverter 410 is configured to divert theincoming flow of fluid to either lateral side of the flow diverter 408,e.g., to improve dispersion of the fluid in the cavity 402, andtherefore over the nozzle plate 106. Moreover, the varying depth of thecavity 402, e.g., resulting from the tapered or angled upper cavitysurface 406 may help to normalize fluid pressure in the cavity 402. Forinstance, as cooling fluid enters the cavity 402, some of the fluidpasses through the nozzle plate 106, thereby reducing the amount offluid that advances to distances farther from the second opening 420.The angled upper cavity surface 406 reduces the volume or headspaceavailable to the fluid farther from the second opening 420, therebymaintaining a more consistent pressure, even when less fluid is present.

Modifications to the cover 108 also are contemplated. For example, theflow diverter 410 may be other than axially-aligned with the passageway408. The ridge 412 may be angled relative to the axis of the passagewayor curved, for instance. Moreover, the angles of the lateral sides 414may be varied. The upper cavity surface 406 may also be altered from theillustrated example. In some instances, the upper cavity surface 406 maybe parallel to the bottom surface 404. For instance, a constant distancebetween the upper cavity surface 406 and the bottom surface 404 may befrom about 0.25 mm to about 1.0 mm. In still other embodiments, theupper cavity surface 406 may include additional angles to further alterthe volume defined by the cavity 402. For instance, while FIGS. 4A-4Ccontemplate only a two-dimensional taper, e.g. from a side proximate thenozzle to an opposite side, the upper cavity surface may angle inthree-dimensions. In one example, the upper cavity surface may befarthest from the bottom surface 404 proximate the second opening 420and angle toward the bottom surface 404 in all directions. For instance,the upper cavity surface 406 may have a same distance from the bottomsurface 404 at radial distances from the second opening 420.

FIGS. 5A and 5B are cross-sectional views taken along section lines5A-5A and 5B-5B, respectively, in FIG. 2 . Additional features andoperation of the cooling apparatus will be detailed further inconnection with FIGS. 5A and 5B.

As illustrated in FIG. 5A, the frame 104 is coupled to the base 102, thenozzle plate 106 is coupled to the frame 104, e.g., on the first ledge124 a, and the cover 108 is coupled on the frame, e.g. on the secondledge 124 b and/or the nozzle plate 106. The cover 108 and the nozzleplate 106 define a first volume 502, e.g., an inlet volume. The nozzleplate 106, the frame 104, and the base 102 define a second volume 504,e.g., an outlet volume. The first volume 502 generally corresponds tothe cavity 402 in the cover 108, discussed above. The fins 114 aredisposed in the second volume 504.

In operation, cooling fluid, e.g., a single-phase cooling fluid, whichmay be water, refrigerant, or the like, is introduced into the firstvolume 502 e.g., via the inlet port 144, generally as shown by thearrows 506. As detailed above, the fluid may be diverted by the flowdiverter 410 and/or compressed by the upper cavity surface 406. As thefluid is dispersed through the first volume 502, the fluid also passes,e.g., under the influence of gravity and/or pressure from the incomingfluid, through the nozzle plate 106, via the flow paths 138. Morespecifically, the fluid generally emerges from the nozzle plate 106 astransversely-expanding fluid jets, generally as shown by arrows 508. Inthis example, the flow paths 138 are configured to direct the jets toimpinge the base 102, e.g., the fins 114 or spaces between the fins 114,at an angle. In this example, an x-component of the jets represented bythe arrows 508 is opposite that of an x-component of the flow of thefluid entering the inlet volume 502, e.g. represented by the arrows 506.As noted above, the cover 108, and thus the inlet port 144, may beconfigured in four orientations, in which the fluid flow represented bythe arrows 506 can be otherwise oriented relative to the flow paths 138.Because of the construction of the nozzle plate, a predominant directionof flow above the nozzle plate, e.g., in the first volume 502, may beirrelevant to performance of the flow paths 138. The jets emerging fromthe nozzle plate 106 enter the outlet volume 504, impinge the base 102,and pass toward an outlet, e.g., generally as shown by arrows 510. Atthe outlet, the fluid may be transported away from the cooling apparatusvia an outlet port (such as the outlet port 132, not shown in FIG. 5A).As noted above, the emerging jets are angled relative to the base 102,and the nozzle plate 106 may be arranged such that the angled jets aredirected generally toward the outlet port. In this arrangement, jetsfarther from the outlet port may help “push” fluid toward the outlet. Inother examples, one or more channels, diverters, or other features maybe used to direct fluid from the outlet volume 504 toward the outletport.

FIG. 5B shows the cooling apparatus 100 in the y-z plane (of FIG. 2 ).The view of FIG. 5B better shows the lateral aspects of the flow paths138 and their impact on fluid flow through the nozzle plate 106. Morespecifically, and as detailed above, the flow paths 138 increase inwidth, e.g., from the inlet width, w_(i), to the outlet width, w_(o). Asa result, the jets emerging from the flow paths 138, that is, into theoutlet volume 504, are transversely expanding, generally as shown by thearrows 512. Accordingly, in addition to being angled in the x-z plane,as shown in FIG. 5A, portions of the jets emerging from the nozzle plate106 also are angled in the y-z plane. The transversely expanding jetsmay have a transverse velocity that is at least ten percent of the axialvelocity of the jet and results from the design of the flow paths 138 inthe nozzle plate 106. The transversely expanding jets of this disclosureare distinguished from natural expansion of a jet entering a low or zeromomentum fluid into which the jet is injected. As detailed above, thetransverse expansion may be further achieved using a nozzle design, suchas via the geometries of the inlet 302, the undercut 318, and/or thechannel 316. The flow paths produce single-phase, transversely expandingfluid jets that provide effective cooling without atomization or otherresource-intensive techniques, e.g., based solely on the geometry of theflow paths 138, including the channel 316 and/or the nozzle formed atleast in part by the undercut 318.

As will be appreciated, modifications to the nozzle plate 106 may becontemplated. For example, the number and arrangement of the flow paths138 will impact a surface area impinged by the jets. Moreover, each ofthe flow paths 138 may be configured to have a specific pressure lossprofile as a function of flow rate and/or the number of flow paths maybe selected to limit the total flow of fluid at a specific pressureloss. Moreover, a distance between the nozzle plate and the base may bemodified to alter the surface area associated with impingement, e.g., alarger distance will result in a larger surface area, but lower velocityat impingement, whereas a shorter distance will provide a reducedsurface area, but higher velocity, at impingement. In examples, theheight of the nozzle plate relative to the base may be altered byadjusting a distance of the first ledge 124 a from the bottom surface118 of the frame 104. In some examples, the nozzle plate 106 may be fromabout 0.1 to about 10 mm from the impingement surface, where theimpingement surface may be the fins 114 and/or the top surface 112 ofthe base 102. In some examples, the inventors have found that thedistance of the nozzle plate 106 from the impingement surface may beminimized relative to conventional arrangements. For instance, becausethe jets produced by the flow paths 138 are expanding through thethickness of the nozzle plate 106, the area of impingement proximate theoutlets 304 may provide sufficient cooling. Accordingly, reduceddistances, e.g., from about 0.1 mm to about 1 mm may provideimprovements such as those described herein, and with a reduced profilefor the cooling apparatus 100.

As illustrated in FIG. 5A, the jets, generally shown by the arrows 508have a horizontal component, e.g., in the x-direction, and the fins 114are generally arranged in this same direction. As a result, the angledjets may act to “push” fluid along the base 102. In some examples, thejets may be angled toward the outlet port 132. Moreover, by aligning theangled jets generally as shown in the examples, jets further from theoutlet port 132 will “push” fluid coming from jets closer to the outletport 132 toward the outlet port 132, to effectively carry heat towardthe outlet port 132. In the illustrated example, the jets are angled topush fluid along channels formed between the fins 114. However, in otherexamples the fins 114 may be rotated about the z-dimension, such thatthe horizontal component of the emerging jets is not in line with thefins 114. For example, configuring the nozzle plate 106 to be normal tothe shown orientation may result in the angled jets contacting faces ofthe fins 114, which may improve heat dissipation in some examples. Inthis instance, fluid may collect in the channels between the fins 114and/or move laterally relative to a direction of the outlet. The fluidmay be otherwise directed toward the outlet e.g., using additionalchannels, by re-positioning the outlet, or the like. Also, althoughexamples described herein illustrate the flow paths 138 as beingsubstantially aligned, e.g., having a same or similar offset betweeninlet and outlet, such is not required. In other examples, the flowpaths 138 may be configured to direct flow in multiple directions,including two directions that are substantially opposite each, that arenormal to each other, that converge, or that are otherwise angledrelative to each other. In additional examples, the flow paths 138 maydirect fluid in three or more directions, e.g., four orthogonaldirections. The flow paths 138 alternatively may be configured to directflow radially inwardly, e.g., toward a center point, a point proximatethe outlet, or the like, or to direct flow radially outwardly, e.g.,diverging from a point or region. In some examples, the arrangement ofthe flow paths 138 and the transversely expanding jets resultingtherefrom may be configured to complement a fin arrangement on the base102, based on a thermal load of the component to which the coolingapparatus 100 is to be secured, or the like.

FIGS. 6A-6C show portions of additional examples of nozzle plates, likethe nozzle plate 106. More specifically, FIGS. 6A-6C may besubstantially the same as the magnified portion 304 of FIG. 3A, but withvaried inlets. FIG. 6A shows a first nozzle plate 600 in which firstinlets 602, e.g., which are inlets to flow paths such as the flow paths138, are substantially circular. Here the inlet width, w_(i), is adiameter of the circular inlet 602. FIG. 6B shows a second nozzle plate604 in which second inlets 606, e.g., which are inlets to flow pathssuch as the flow paths 138, are oval. In this example, the inlet width,w_(i), is the major diameter of the oval inlet 606. In other examples,the inlets 606 may be rotated relative to the orientation shown. FIG. 6Cshows a third nozzle plate 608 in which the third inlets 610, e.g.,which are inlets to flow paths such as the flow paths 138, aresubstantially square. In this example, the inlet width, w_(i), is alength of a side of the square inlet 610. As will be appreciated, inletconfigurations other than those illustrated herein may be used withoutdeparting from the spirit and scope of the disclosure.

FIGS. 7A and 7B show portions of additional examples of nozzle plates,like the nozzle plate 106. More specifically, FIGS. 7A and 7B may besubstantially the same as the magnified portion 308 of FIG. 3B, but withvaried outlet configurations. FIG. 7A shows a first nozzle plate 700 inwhich first outlets 702, e.g., which are outlets of flow paths such asthe flow paths 138, are substantially oval. In this example the outletwidth, w_(o), is a major diameter of the oval outlet 702. As describedherein, the outlet width, w_(o), may be chosen to achieve the desiredtransversely-expanding, single phase fluid jets, e.g., in conjunctionwith the inlet and/or a nozzle-like geometry proximate the inlet. FIG.7B shows a second nozzle plate 704 in which second outlets 706, e.g.,which are outlets of flow paths such as the flow paths 138, aresubstantially rectangular. In this example, the outlet width, w_(o), isthe length of a longer side of the of the rectangular outlet 706. Asdescribed herein, the outlet width, w_(o), may be chosen to achieve thedesired transversely-expanding, single phase fluid jets, e.g., inconjunction with the inlet and/or a nozzle-like geometry proximate theinlet. As will be appreciated, outlets other than those illustratedherein may be used without departing from the spirit and scope of thedisclosure. For instance, other polygonal, arcuate, linear, and/or otherconfigurations may be used.

FIGS. 8A and 8B show portions of additional examples of nozzle plates,like the nozzle plate 106. More specifically, FIGS. 8A and 8B may besubstantially the same as the magnified portion 318 of FIG. 3B, but withvaried flow path configurations. FIG. 8A shows a first nozzle plate 800in which a first flow path 802, e.g., which may correspond to one of theflow paths 138, extends from an inlet 804 to an outlet 806. For example,the inlet 804 may be any of the inlets described herein and the outlet806 may be any of the outlets described herein. The flow path 802comprises a single channel having a substantially constant thickness,t_(n), from the inlet 804 to the outlet 806, unlike the channel 316,which included the undercut 318. The flow path 802 may result in alarger inlet thickness, than that shown in FIG. 3A, e.g., the inletthickness, t_(i), and the outlet thickness, to, may be the same. In thisarrangement, the nozzle-effect discussed above, in which geometryproximate the inlet causes transverse expansion of fluid, may not be asapparent, although because the flow path 802 includes a channel angledrelative to a top surface of the nozzle plate 800, some expansion mayoccur. Regardless, the expansion of the flow path 802, e.g., in adirection normal to the plane of FIG. 8A, will still result intransversely expanding jets exiting the outlet 806, in accordance withaspects of this disclosure. Alternatively, the nozzle thickness, t_(n),may be vary from the inlet 802 to the outlet 804.

FIG. 8B shows a second nozzle plate 808 in which a second flow path 812,e.g., which may correspond to one of the flow paths 138, extends from aninlet 812 to an outlet 814. For example, the inlet 812 may be any of theinlets described herein and the outlet 814 may be any of the outletsdescribed herein. The flow path 810 has a nozzle portion 816 proximatethe inlet 812 and a channel portion 818 proximate the outlet 814. Inthis example, the flow path 810 has a substantially constant thickness,t_(n), from the inlet 804 to the outlet 806, unlike the flow path ofFIG. 3C, which included the undercut 318 as the nozzle portion. However,instead of extending generally along a constant axis, as with thechannel 802 and the channel 316, the nozzle portion 816 is angledrelative to the channel section 818. More specifically, the nozzlesection 816 is substantially normal to a top surface 820 of the nozzleplate 808, and the channel section 818 is angled, e.g., at a channelangle θ relative to a bottom surface 822 of the nozzle plate 808. Asdescribed herein, cooling apparatuses like those described herein may beconfigurable to allow for fluid to enter the inlet volume above thenozzle plate 808 from a number of different directions. Forming thenozzle section 816 of the flow path 810 substantially normal to the topsurface 818 may ensure consistent functionality of the nozzle plate 808,regardless of a relative orientation. Moreover, the nozzle section 816,as with the undercut 318 discussed above, may impart a transverseexpansion, e.g., at a transition from the nozzle section 816 to thechannel section 818, on fluid passing through the flow path 810, as inthe example of FIG. 3C discussed above.

Although not visible in the examples shown in FIGS. 8A and 8B, the widthof the flow paths 802, 810 expand laterally, e.g., in a direction normalto the plane of the FIGS. 8A and 8B, from a position proximate therespective inlet 804, 812 to the respective outlet 806, 814 to providethe transversely expanding fluid flow. In the example of FIG. 8B, thenozzle section 816 may have a constant lateral width, but the channelsection 818 may expand laterally. As will be appreciated, flow pathsother than those illustrated herein may be used without departing fromthe spirit and scope of the disclosure.

It will be appreciated that the foregoing description provides examplesof the disclosed system and technique. However, it is contemplated thatother implementations of the disclosure may differ in detail from theforegoing examples. All references to the disclosure or examples thereofare intended to reference the particular example being discussed at thatpoint and are not intended to imply any limitation as to the scope ofthe disclosure more generally. All language of distinction anddisparagement with respect to certain features is intended to indicate alack of preference for those features, but not to exclude such from thescope of the disclosure entirely unless otherwise indicated.

Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context.

While aspects of the present disclosure have been particularly shown anddescribed with reference to the embodiments above, it will be understoodby those skilled in the art that various additional embodiments may becontemplated by the modification of the disclosed machines, systems, andmethods without departing from the spirit and scope of what isdisclosed. Such embodiments should be understood to fall within thescope of the present disclosure as determined based upon the claims andany equivalents thereof

What is claimed is:
 1. A cooling apparatus comprising: a base configuredfor securement proximate an electronic component; a cover coupled to thebase; a nozzle plate coupled to the base and the cover, the nozzle platedividing an interior volume of the cooling apparatus into a first volumedefined, at least in part, by an interior surface of the cover and afirst surface of the nozzle plate and a second volume defined, at leastin part, by the base and a second surface of the nozzle plate, thenozzle plate comprising: a plurality of flow paths extending from thefirst surface of the nozzle plate to the second surface of the nozzleplate, an individual flow path of the plurality of flow paths comprisinga channel extending from an inlet in the first surface of the nozzleplate to an outlet in the second surface of the nozzle plate, the inlethaving a first area in a plane of the first surface and the outlethaving a second area, in a plane of the second surface, larger than thefirst area such that single-phase fluid in the first volume passesthrough the nozzle plate via the plurality of flow paths and enters thesecond volume as transversely expanding fluid jets; an inlet portconfigured to provide the single-phase fluid to the first volume; and anoutlet port configured to allow the single-phase fluid to exit thesecond volume.